Death of a Hero
by DisasterMaster445
Summary: Finn dies in a battle, but his body disappears. His friends are distraught, and his girlfriend is ready for murder. The news of the well-liked hero's death spreads far beyond the Candy Kingdom, reaching the ears of Prince Gumball's kingdom. A boy from Finn's past-before he was found in that forest-surfaces for revenge. Finn, Jake, Fiona, Cake, Bubblegum, Gumball, Marceline, Marshal
1. The Last Adventure?

**Death of a Hero**

**By: DisasterMaster445**

**Really been wanting to do an multi-chapter Adventure Time fic, but just got around to it. This is gonna be a more adult version of Adventure Time. Not adult like sex or anything, more like violent. This is gonna be what an Adventure Time anime would be like. So, the main characters will be Finn, Jake, Marceline, Bubblegum, and their counterparts from Fiona and Cake, along with an unknown character from Finn's past. Someone from before Finn was abandoned in that forest when Jake's parents found him.**

* * *

**Chapter One: The Last Adventure?**

* * *

It wasn't supposed to be like this… It was a simple fight with the Ice King, but it didn't end well…not well at all. The blond boy was laying on the ground, iconic hat tore away and leaving his shoulder-length locks wet from the snow of the mountains. His girlfriend, the princess made of flames, stood flickering in the cold air. A circle of melted snow spread from underneath her and hot tears of flame dripped down, throwing up steam.

"Damn it!" She cursed, voice shaky. The yellow dog, the boy's best friend, stretched back up to the peak the girl stood on. He'd been chasing after the one who did this, but came back as soon as he heard the girl's exclamation. He stared down at his best friend, ashamed with how his family's sword was being put to use. The Demon Blood Sword was sticking straight out of Finn's stomach, pinning him to the ice.

"Joshua! Give me my blood!" Jake whirled around, glaring at the muscular Blood Demon. "Come on, man! I need that blood!" "_Kee Oth Rama Pancake!_" Jake yelled, utilizing the spell his father inadvertently showed him when Finn got the sword. The demon cursed, vanishing.

"This is terrible…" Jake became somber again. "Let's go, FB." He began to walk away, and Flame Princess looked at his retreating back for an instant. Then she looked back. "Jake!" She called. The dog rushed back, quickly seeing the problem. Finn's body was gone!

* * *

A few kingdoms over, in a land ruled by Prince Gumball, a blond boy stirred. He was sitting on a couch in his girlfriend's house, said girlfriend with her head on his shoulder. Her cat was curled up in his lap. "Ugh…" He groaned, staring at the flickering lights of the television. "Fiona…" He shifted, causing her to latch onto his arm in her sleep and the cat to twitch. "Damn…Fiona." He said louder. She opened her eyes, looking up at him sleepily.

"What's up?" He looked at the ceiling, troubled. "I've got a bad feeling…"

* * *

**A Week Later**

* * *

News about Finn's murder circulated around the kingdoms, and hundreds of people were meant to be at his funeral. That was how the blond boy found out. As soon as he read that article, he was sure. This was the boy he'd been looking for, and yet he was dead. He knew the kingdom, or course. Gumball's cousin, Princess Bubblegum, ruled that kingdom, so he knew it would be no problem getting hold of them.

"Fiona, we need to get to the castle." The blond girl looked confused. "Why?" "I've gotta see Gumball." Fiona shrugged and grabbed her hat. Oddly enough, it was his old hat, and was identical to the hat Finn wore. "Come on, Cake."

* * *

At the castle, Gumball and Marshall were in the throne room, arguing. "Dude!" The vampiric rock star exclaimed. "Just call Bubblegum! We've gotta know if this 'Finn' kid is the guy he's been looking for!" "I understand that." The Prince said calmly. "But I don't want to bother her with this. She's going through enough right now. From what I understand, she really cared about him."

"That's the point! Wouldn't she like to know if this kid had family?!" "Oh, come now." Gumball said. "No, seriously! He's a human, this kid's a human, that _can't_ be a coincidence!" The Prince laughed. "That means nothing. Fiona is human. She's not related to him."

"Guys." Both boys turned. "H-hey, man." Marshall stuttered. "How long have you been there?" Gumball asked nervously. "Long enough. Listen, I _know_ this 'Finn' is the one I've been looking for. I've gotta get to the Candy Kingdom." The pink boy looked exasperated.

"How can you possibly know?" "You just have to trust me. I have a feeling." The boy looked emotional, something neither of his best friends could associate with the warrior. Fiona stepped up next to her boyfriend, grabbing his hand in a show of support.

"Gumball, we really need to make the trip." She said quietly. Gumball looked at the two of them for a second, and at Cake the cat behind them, and nodded. "Normally I wouldn't allow such a thing, but you're my best friend…" He stroked his chin thoughtfully.

"Do you have your staff?" The boy nodded. "I always have my staff." Gumball stomped the floor twice. "Lord Monochromicorn!" He beckoned. A swirl of shadows appeared on the ground, and a black unicorn stepped up out of it. His mane was grey, and as he came from the shadows, his body just kept coming, seeming to stretch. Finally, he exited the hole.

"Hey, gorgeous!" Cake shouted. Monochromicorn clacked his hooves against the ground in Morse code, whinnying. Thunder crashed. _"Hey!"_ "Mo-Chro," Gumball interrupted. "I need you to take these three to see Bubblegum." He nodded, snorting. "Four." Marshall interjected. He turned to Gumball.

"I can't leave my friend in the lurch like this." He declared, flashing an all fangs smile. Gumball nodded. "Fine. Go."

* * *

Princess Bubblegum and Marceline were in the princess' throne room, mirroring their relatives only hours before. Both were grieving in their own special ways. Bubblegum was bawling her eyes out, and Marceline was morosely strumming her Axe-Bass.

"Come on, Bubblegum." Marceline tried to soothe. "Maybe it's not what we think. They didn't find the… body." She whispered the last word, but PB began crying in earnest. Jake, who was acting as PB's bodyguard in light of recent events, rushed into the room.

"Princess! Marceline! There's some suspicious guys outside!" However, another pool of shadows formed, Mo-Chro bursting forth with his passengers. "What is the meaning of this?!" Bubblegum shouted, tears forgotten for the moment. The blond boy slid down from Mo-Chro, face green and sickly. Whatever PB and Marceline were going to say was lost as they saw the resemblance. But Jake leapt into action. He stretched out, barreling the boy over.

"Who the hell are you?! And why do you look like Finn?!" He bared his fangs, aimed at the boy's neck. "Wait!" Marceline cried. Jake flicked his eyes to the Vampire Queen, who was embracing another of the intruders.

"Calm down, sis. Jeez. It's not the time." Marshall muttered. Jake was surprised, but kept focused on the boy. "_Answer me!_" The boy glared hatefully at the dog. "I'm Jinn, of the Humans! And Finn was my brother!"

* * *

**So, that's that. This mysterious blond boy is Jinn, Finn's brother, and one of the last humans in Ooo. He's heard about Finn in the news, and has been searching for his baby brother for a long time. Ever since he got a vision that his brother might be alive. He's formed a team of his girlfriend, Fiona, her cat, Cake, his best friend, Marshall, who is Marceline's little brother, and Lord Monochromicorn, Cake's boyfriend and Gumball's trusty steed. This team is in Ooo to find out what happened to Finn the Human, and to gain revenge for Jinn's long lost brother. Who killed him? Finn was fighting with the Ice King, but is he the culprit? He's said he never wanted to kill Finn, but did something change his mind? Or is something more sinister at work here? Follow me to find out. Ja Nae.**


	2. Sad Tales

**Death of a Hero**

**By: DisasterMaster445**

**Sorry for not updating in so long, but I've been busy with college, and I've had computer problems. I'd like to thank everyone who's read, favorited, or followed. I hope to exceed your expectations. Finn's dead. The people of the Candy Kingdom are beside themselves with grief, and rightly so. Finn touched the lives of everyone in the kingdom, whether for the good, or the bad. The Ice King is to blame, but nobody really knows what happened during that fight. Jinn, another Human who lives a few kingdoms over, is Finn's brother. He and his posse of friends have traveled to the Candy Kingdom to discover the truth behind the blond boy's demise. Something sinister is DEFINITELY afoot. Btw, time-wise, the fic takes place during season 4, before the episode 'I Remember You.'**

* * *

**Chapter Two: Sad Tales**

* * *

After ten more minutes of barking and growling, Bubblegum forced Jake to let Jinn stand. The boy frowned and wiped Jake's frothy dog-spit from his shirt. He'd dressed in his lightest killing clothes in preparation for hunting; a white v-neck t-shirt, baggy black jeans, and white tennis shoes. For colder areas he had a blue flannel shirt stowed in his pack. His blond hair was cropped short.

He had a leather strap slung across his body from left shoulder to right hip. His staff was attached to it the opposite way; right shoulder to left hip. It was six feet long, made of polished metal that glowed occasionally with an orange light.

Jake sniffed the air, as if noticing it for the first time. "What's that?" He demanded, still distrustful of the boy. He stretched a finger to the staff. "It's my staff. Forged with the blood of seven shamans." Jake's eyes narrowed even more, nearly slits.

"That's enough, Jinn." Fionna interrupted, placing a hand on her boyfriend's shoulder. "It's a dog, and yet there's enough testosterone in here to kill a horse." Mo-Chro snorted, hoofing the ground angrily.

"Hey, man." Marshall snickered. "Watch your snout." Bubblegum sighed heavily. "This is getting us nowhere. What are you doing here?" She asked Jinn. "Why didn't you come sooner? Finn thought he was alone…" She trailed off. "…You could've prevented it."

"…No." Jinn's face fell. "I couldn't have. I didn't know where he was. I didn't even really know if he was alive." Jake glared at him skeptically. "Oh, really?" Jinn returned the dog's gaze with one of equal intensity. "Really." "Then why've you been looking?" Marceline asked. "I just had a feeling…" He muttered. He shook his head.

"You're stupid questions aren't helping anything. I need to know what happened, so I know what to hunt." Jake was still skeptical, but with some prodding from Bubblegum he began spinning his tale.

* * *

_It was supposed to be simple. Finn and Jake were spying on the Ice King. They'd heard from Wildberry Princess that the crazy old man was stalking around the grounds of various other princesses. They were stationed on one of the many icy mountains that surrounded the Ice King's main peak._

"_I dunno about this man," Jake said. "Something seems off." Finn looked at his friend for a moment. "I think you're just paranoid. This seems right up Ice King's alley." Jake stroked his chin._

"_When's Flame Princess supposed to get here?" The dog asked. "We're supposed to send her a signal when the Ice King goes on the move." "How're we supposed to do that?" Finn jerked his head at the fire they had going beside them._

"_Isn't this fire kinda conspicuous?" Finn smiled. "Quit playing around, Flambo." In front of Jake's eyes, the fire transformed into their small, catlike friend. "'Ey, youse guys." Jake nodded. "You remember your part of the plan, right?" Finn grilled. Flambo nodded._

"_When dat Ice King fella takes off, I gotta haul tail, and find da dame." "Good, 'cause I think I just found him!" "Where?" Jake began looking around. "Get down!" Finn whispered, pulling the dog down beside him in the snow._

"_Get moving, Flambo!" The boy hissed. The small creature nodded again before he vanished in a burst of smoke. Finn drew the Demon Blood Sword and jumped off the mountain. Jake rolled his eyes, jumping as well. He stretched under the boy, catching him, and began running after the retreating figure of the Ice King._

"_Looks like he's headed for Princess Bubblegum's castle." Jake mused, trying to keep quiet. Finn nodded absentmindedly, looking back behind him. He could see a bright trail zigzagging a safe distance behind him, signaling the arrival of his girlfriend._

"_Flame Princess is here." He lifted Jake's ear, whispering. Jake risked flicking his eyes behind them for a moment, seeing the same trail. "Good. She's always good backup for fighting the Ice King." The duo finally left the Ice Mountains, still trailing behind the crazy man who flew with his beard._

"_Is he going down?" Finn asked. "Looks like it." Jake agreed. "But…that's not right. Princess Bubblegum's castle is further on." Jake shrank back to normal size, and Finn jumped off him. They moved forward slowly, listening to the Ice King mutter as he fiddled with something on the ground._

_Jake stepped on something, and the Ice King froze. He quickly stuffed whatever it was he was messing with into his robes, turning around. He cocked his head inquisitively. "Oh. It's just you guys." He was wearing a guilty smile._

"_What're you up to, Ice King?!" Finn shouted. The Ice King lifted his hands, trying to placate the young man. "What're you talking about? I was just taking a fly around, and _Kunai Attack_!" He reached into his sleeve, throwing a dozen icy knives at the pair._

"_Crap!" Finn cried, diving to the side. "Jake!" He yelled. "I thought the Ice King didn't like using Fridjitsu!" Jake shrugged, dodging another round of knives. "Well, two can play this game!" Finn shouted._

"_No, only _he_ can play this game, remember?! We forgot the incantations!" "Force of Blizzard!" The blue man cried, throwing up his palms. Finn and Jake were blasted back by a wave of snow, completely covered._

_Ice King smiled evilly for a moment, before having to dodge a fireball. "What?!" He glared at the arrival of Flame Princess. "Where'd _you_ come from?" He demanded. She was standing on the snow covering her boyfriend and his dog, causing it to slowly melt. Flames flickered higher around her, and the snow melted quicker. The Ice King glared hatefully at her, exuding a greenish-blue energy. The snow finally disappeared, and the two warriors stood back up. Ice King smiled again._

"_Snowblind!" He vanished in a burst of more snow. They heard a short cry of pain, but Jake was preoccupied. He saw the retreating form of the Ice King, and gave chase. Flame Princess turned toward the cry._

"_Damn it!" She cursed. Jake heard her cry, racing back. He stared at Finn, lying on the ground with the Demon Blood Sword sticking out of his stomach._

"_Joshua! Give me my blood!" Jake whirled around, glaring at the muscular Blood Demon. "Come on, man! I need that blood!" "_Kee Oth Rama Pancake_!" Jake cried. The demon cursed, vanishing._

"_This is terrible…Let's go, FP." He began to walk away, and Flame Princess looked at his retreating back for an instant. Then she looked back. "Jake!" She called. The dog rushed back, quickly seeing the problem. Finn's body was gone…_

* * *

"There." Jake said sadly. "I told _my_ story. What's yours?" Jinn glared at the demanding pooch, but jumped into a tale of his own.

"It all started during the Mushroom War. It was the eradication of millions. It was finished just 1007 years ago with the dropping of something called the Atomic Bomb. Not much is known nowadays of the bomb, but then it was a last resort in war." Jake looked to Bubblegum for confirmation. She nodded. Jinn took that as a cue to continue.

"Humans were the dominant species at this time. Two sides waged this war, each vying for control over the rest of the world, now known as Ooo. Both sides had such bombs, and had ways of knowing when the other side fired." They looked to Bubblegum again, but this time she shrugged, not knowing this part of the story herself.

"Both ended up unleashing the bombs, desolating the land, and killing all the humans. Well, almost all of them. Two families managed to survive by vanishing into another, demonic world. One of the two men had been forewarned just seven years in advance by a wandering psychic.

"The man's name was Djinn (pronounced Jinn), and the world was uninhabited. He'd only managed to bring the families to this world by an ancient ritual, written in a book long since lost. He learned the spell from an antiquarian named Simon something." Marceline's eyes widened.

"The realm was a reddish color, and much of the land was covered by a lake of black ooze. Djinn dubbed the place, 'The Nightosphere.'" He was interrupted by Marshall.

"You never told me about that." He glared at his friend. Jinn sighed. "Let me finish the story, and you can rage as much as you want. There's a lot more you have to know…" Marshall looked about to argue, but Marceline placed a hand on his shoulder. "Fine." He spat.

"Thanks. Anyway, Djinn dubbed the land 'the Nightosphere.' The Nightosphere graced the two families increased longevity. Djinn's son soon grew strong and wanted to go back out into the Human World, but Djinn worried about how the war would end. He refused his son's wishes."

"Where was our father during all this?" Marceline asked. "I'm getting to that. You shouldn't rush the story; you won't like what happens. The son's name was Flynn, and he didn't like being contained. He had just married before his family escaped to the Nightosphere, and so he and his bride often tried to leave the Nightosphere. But his father was always one step ahead.

"One day, when his father wasn't around, Flynn tried once more to escape. However, the man from the other family tried to stop him. In a desperate fight, the man was knocked into the lake of black ooze. His name was Hunson Abadeer." Marshall's glare intensified as he flung himself at Jinn.

"You _lie_!" Jinn pulled his staff out, ready to defend himself, but Jake stretched around the dark-haired boy, restraining him. "Release me!" He strained, but was unable to escape the dog's grasp.

"Keep talking. I want to hear the rest." The dog said. Jinn nodded. "The man absorbed the ooze, morphing into the Hunson Abadeer you know today. Flynn, filled with grief and guilt, stayed in the Nightosphere with his family, while Hunson tried to keep his small family together. However, it wasn't working. Hunson's wife was pregnant, and she was afraid of him. He was becoming cruel, but he still loved her, and realized he was losing himself. He left the Nightosphere, while the War still waged.

"Flynn's wife, Lynn, was also pregnant. She tried to help Hunson's wife through the man's transformation and subsequent abandonment, but the woman spiral ever closer to madness and death. The end of the War had come to pass, and Hunson returned to the Nightosphere a changed man. He was cold, and cruel. He looked for Flynn's family, and his own wife, but they had hidden from him."

Marceline's memories filled in the gaps as she listened to the story. She knew she was alive when the war had ended, but her supposed mother was still pregnant in the Nightosphere…so who was that child?

"The increased longevity the Nightosphere provided prolonged not only the lives of the humans trapped there, but also prolonged the pregnancy of the two women. Several hundred years passed, seeming like days to the hiding humans, before Lynn finally went into labor. The humans went deeper into hiding, fearful that Lynn's screams of pain would draw the attention of Hunson or the masses of demons that he'd seemingly created as his subjects. She was in labor for weeks, finally delivering a boy. It wasn't long after that Hunson's wife went into labor herself."

That solidified it in Marceline's mind. She was already on Earth when this was happening. She remembered when her father went back to the Nightosphere; when he abandoned her. Therefore, this woman wasn't her mother. And the child wasn't Marshall, either. He was only a 200 years younger than herself, which was far before this child's birth. According to Jinn, of course. Who was to say this story wasn't complete fiction?

"The woman had been through hell by Hunson's transformation, and his leaving her. She had completely lost her sanity, and most of her strength. She didn't make it through the birth. Flynn and Lynn took the baby girl, resolving to take care of her themselves. That was twenty years ago." Bubblegum's mind was working in overdrive, striving to finish the story before Jinn told it.

"Are we to understand that you and Fionna are the two babies born in the Nightosphere?" Marceline's and Marshall's eyes widened, along with the other three in the room; Jake, Cake, and Lord Monochromicorn. Jinn nodded.

"My parents, and by extension Finn's parents, were Flynn and Lynn. And Fionna is Hunson Abadeer's non-supernatural, fully human daughter." Fionna nodded solemnly, affirming her boyfriend's story.

"But, that's not the end of the story. My grandfather decided it was time to escape. His wife, my grandmother, had died in the Nightosphere, and there wasn't anything keeping him there any longer. My father would finally get his wish. My mother and father wanted to lay Hudson's wife to rest, so they tried to take her from hiding with us. When we left hiding, we were immediately under Hudson's eye. As he so rightly put it, 'no one leaves the Nightosphere.'

"He attacked, not caring about his daughter, or his wife's body. My grandfather leaped into action with the family staff, which I now carry with my. He held Hunson for an instant before he transformed into his giant form. It gave my father the time he needed to open a way to the Human World. His father threw him the staff just as Hunson finished him off.

"He jumped at us, but we were already through the portal. My father used the power of the staff to close the door before Hunson could get us. However, the world wasn't anything like it used to be. We'd appeared in Gumball's kingdom, but his father was the ruler. He took us in, astounded by the fact that a few humans survived the Mushroom War.

"Gumball's father filled my father in on what had happened the last 987 years, and was amazed that my father had only aged 15 years. They became good friends and the king even had Fionna and I trained with Gumball as we both grew up. But my father was killed 12 years ago. Fionna and I were away at the castle, while my mother and father took my year-old little brother, Finn, on a picnic. When Fionna and I went to join them, we found them torn apart, and Finn was gone." He looked at the ground, and Fionna took his hand. She smiled comfortingly.

"I thought Finn was dead, but there was no body. To be sure, I've spent every possible moment since then looking for him. Until now; now I have to look for his killer." Marshall was still livid.

"You little bastard! You were my best friend, and you didn't tell me _any_ of this! Nothing about my father!" "Marshall." Marceline admonished. "Shut up. It's all over and done with. There's something more important. We have to find the Ice King." She looked saddest of all, knowing what would probably happen to her old friend Simon Petrikov.

* * *

**I think I should probably end it there. I'm not exactly sure how people are going to feel about me jacking up so much of the Adventure Time universe in just seven pages of Microsoft Word, but I hope you all don't COMPLETELY hate me for it. I had to give a reason for there being two more humans in Ooo, and I had to give them both a backstory. So there you have it. Djinn the human was warned by a psychic how the Mushroom War would end. He got a ritual from the future Ice King, Simon Petrikov, and took a group of humans into the Nightosphere to wait out the war. The book the ritual came from would be the Enchiridion, which was discovered by Simon Petrikov. Flynn, not wanting to be contained in such a nightmarish realm, tried to escape and turned Hunson Abadeer into what he is today. So, in truth, Marceline and her brother owe their lives to Jinn's family. If you guys reading this don't hate me, next time we'll see the hunt for the Ice King. Ja Nae.**


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